Lauderdale County is a county located on the eastern border of the U.S. state of Mississippi. As of the 2020 census, the population was 72,984. The county seat is Meridian. The county is named for Colonel James Lauderdale, who was killed at the Battle of New Orleans in the War of 1812. Lauderdale County is included in the Meridian, MS Micropolitan Statistical Area.

Meridian is the eighth most populous city in the U.S. state of Mississippi, with a population of 35,052 at the 2020 census. It is the county seat of Lauderdale County and the principal city of the Meridian, Mississippi Micropolitan Statistical Area. Along major highways, the city is 93 mi (150 km) east of Jackson; 154 mi (248 km) southwest of Birmingham, Alabama; 202 mi (325 km) northeast of New Orleans, Louisiana; and 231 mi (372 km) southeast of Memphis, Tennessee.